Thomas archibald goodchild and archibald campbell tait bond



7 UNITED STATES PATENT OEEIcE.

THOMAS AROI-IIBALD GOODCHILD AND AROHIBALD CAMPBELL TAIT BOND, OFLONDON, ENGLAND.

PROCESS OF PRODUCING WATER-MARKS IN OR N MANUFACTURED PAPER.

SPECIFICATION forming part of Letters Patent No. 625,255, dated May 16,1899.

Application filed December 27, 1898. Serial No. 700,454, (No specimens.)

To all whom it may concern.-

Be it known that we, THOMAS ARCHIBALD GOODOHILD and ARCHIBALD CAMPBELLTAIT BOND, subjects of the Queen of Great Britain and Ireland, residingat London, in the county of Middlesex, England, have invented a certainnew and useful Process for the Production of Water-Marks in or onManufactured Paper,of which the followingis a specification.

Our invention relates to improvements in the production of disappearingbut repeatedly-revivable water-marks in or on manufactured paper; andthe object is to attain this result in a simple manner and by theapplication of electricity.

In putting our invention into practice we proceed as follows: Upon aplatinum sheet or plate forming the anode We place a layer of absorbentmaterial, such as blotting-paper, previously moistened with water. Onthis material we place the paper which is to receive the watermark, thepaper having been previously moistened through with water.

\Ve then press face downward on the paper a platinum design of thewater-mark, and this design forms the cathode. We keep the paper incontact with the design for some five to ten seconds, according to thenature of the paper and the amount of electric current used. The resulton removal of the cathode is a distinct and translucent image of thedesign, which gradually fades as the paper dries and finallybecomesinvisible. The mark can, however, be revived and made visible asoften as the paper is immersed in water or moistened in any othermanner.

In our experiments we have employed and found suitable an electriccurrent of one ampere at ten volts.

We offer the following as the most probable explanation of the changeswhich take place in the paper, the explanation being the result ofduly-verified experiments. Ordinary drinking-water contains salinesubstances in solution and that used by us did so to the extent oftwenty grains to the gallon. These saline substances are decomposed bythe passage of the electric current, acids with oxygen being liberatedat the anode and alkalies with hydrogen appearing (as NaHO, 850.) at thecathode, where it comes in contact with the paper, the result being thatthe paper becomes more hygroscopic at these points of contact. WVe havereason to believe, however, that the change is not limited to this, butthat this particular portion of the paper or cellulose combines with anadditional molecule of water, thereby becoming one or other of theglucoses. If we consider the paper (cellulose) as O H O -I-H O, we haveC H- O a glucose or some body resembling it in chemical composition. Thechange may be dueto the nascent hydrogen.

What we claim as our invention, and desire to secure by Letters Patent,is

The process herein described for producing in or on manufactured paper adisappearing but repeatedly-revivable water-mark the said mark beinginvisible ina dry but visible in a moistened condition of the paper, thesaid process consisting in placing on a platinum plate or sheet formingthe anode, a layer of absorbent material saturated with water, inplacing on this and in a moistened state the paper which is to bewatermarked and in pressing face downward on the papera salient or otherplatinum design forming the cathode so thatthe current from asource ofelectricity may pass through that portion of the paper which is incontact with the design on the cathode.

THOMAS ARCHIBALI) GOODCHILI). AROHIBALD CAMPBELL TAIT BOND.

IVitnesses:

. H. PEATREY,

F. Annnnws.

